* Fix#854 Added ViewChannel enum and property to channel permissions
* replaced usages of ChannelPermission#ReadMessages with ViewChannel
* rename parameter of ChannelPermissions constructor
* made OverwritePermissions#ReadMessages obsolete, use ViewChannel instead
* Fix#854 Added ViewChannel enum and property to channel permissions
replaced usages of ChannelPermission#ReadMessages with ViewChannel
rename parameter of ChannelPermissions constructor
made OverwritePermissions#ReadMessages obsolete, use ViewChannel instead
* renamed readMessages parameter in ChannelPermissions constructor and Modify
* fixed channel permission tests to use ChannelPermission enum instead of GuildPermission enum
* replaced usages of readmessages in channel permission tests
* resolve build warnings for permission tests